Java经典算法40例（三十九）

import java.util.Scanner;

/**
* 奇偶
* @author cheng
*
*/
public class ThirtyNine {
public float jishu(int x){
float sum=0;
for(int i=1;i<=x;i=i+2){
sum=sum+1/(float)i;
}
return sum;
}
public float oushu(int x){
float sum=0;
for(int i=2;i<=x;i=i+2){
sum=sum+1/(float)i;
}
return sum;
}
public static void main(String[] args) {
System.out.print("请输入一个正整数:");
Scanner scanner=new Scanner(System.in);
int x=scanner.nextInt();
ThirtyNine thirtyNine=new ThirtyNine();
if(x<1){
System.out.println("请输入正整数！");
}else if(x%2!=0){
float sum=thirtyNine.jishu(x);
System.out.println(sum);
}else if(x%2==0){
float sum=thirtyNine.oushu(x);
System.out.println(sum);
}
scanner.close();
}
}

请输入一个正整数:6
0.9166667